The Aim of the Flow Cytometry Core is to provide access to state-of-the art flow cytometry for all the participants in this Developmental Biology COBRE. The Flow Cytometry Core has two high speed fluorescence activated cell sorters (Dako-Cytomation MoFlo and BD FACSAria) and three analyzers (FACScan, FACSCalibur and LSRll analyzer, all from BD). Dr. Jose Alberola-lla, who is an expert in multicolor analysis and sorting of hematopoietic progenitors, will serve as Core Director and technical assistance will be provided by Dr. Diana Hamilton. Access to the Flow Cytometry Core will be free of charge for all COBRE participants. The research projects of four of the Junior Investigators depend upon flow cytometry and the fifth one proposes flow cytometry as an alternate approach. Thus, this Core will be heavily used and is critical for the success of this COBRE.